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KeepIS
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Posted: 06 November 2018 at 11:09am | IP Logged Quote KeepIS

I thought I'd make a separate post on the trouble I'm having and what looks like the cause.

There is a problem with the ARMmite H7 and these 9" LCD screens in some configurations. The Armmite H7 works perfectly with the the standard MM 7" screen a lot of us use, and it works in both 16 bit and 8 bit connection modes.

I made a quick and dirty adaptor while waiting for the Adpator board designed and provided by Groster Adaptor Thread

These are the two adaptors.



My adaptor worked perfectly with the MM.100+ and the 9" LCD, however on the ARMmite that was wired for 8 bit it gave a tearing effect, shortly after the Adaptor board arrived, I put it together and it worked perfectly in the ARMmite with the 9" LCD in 8 bit mode and wiring.

My adaptor was wired correctly so I assumed it must be lead length on the ground side, it was, I added thick earth lead and it also worked.

Neither will work in the 2nd ARMmite that is wired for 16 bit, they won't work even with the Display driver set to 8 bit mode.

Now I'm not using a BackPack in either of the A-H7 as I haven't assembled the BackPacks yet, in any case both these units are fully assembled controllers. I have a 3rd ARMMite H7 board that I will use to test the 9" LCD with the backpack and the Adaptor board.

The difference between the two ARMmites is this, one is wired for 8 bits, only D0 to D7 are wired up from the A-H7 board to a connector via a short length of RIBBON CABLE, The second unit has D0 to D15 wired the same way.

We know from past experience that Ribbon cable is problematic, and especially longer runs, BTW the strands of the ribbon cables are all separated.

These cables appear to be the problem, the 9" LCD is very sensitive to lead length and possibility crosstalk between the data lines, however the 7" LCD is perfect with these short lead length cables and connectors in both 8 and 16 bit driver modes.

The A-H7 wired for 16 bits has a slightly longer connection cable and the extra 8 wires. Like I said it won't even work with the 8 bit driver loaded.

So for anyone wanting to use these with the ARMmite, you will likely need a BackPack board to keep lead length to a minimum.

Hopefully someone else has an ARMmite-H7 wired up (16 bit) and running with a backpack and a 9" display and can report back, if not, I'll post the outcome here.

Mike.


EDIT: FYI All LCD displays are running from a dedicated and regulated 5V source, dropping Backlight to 20% has no effect, if anything it's worse due to noise from the LCD backlight PWM controller as duty cycle is changed with brightness.





Edited by KeepIS on 06 November 2018 at 11:59am


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KeepIS
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Posted: 06 November 2018 at 2:35pm | IP Logged Quote KeepIS

I managed to get the 9" LCD "almost" running correctly in 16 bit mode with the PCB adaptor board, still using the same ribbon cable to the ARMmite. I had to add a few earth connections in correct positions and the GUI finally rendered correctly, so definitely sensitive to cable length and layout, unlike the standard 5" and 7" displays. I'm now sure that a Backpack on the H7 will solve the problem.


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Grogster
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Posted: 06 November 2018 at 4:15pm | IP Logged Quote Grogster

So, are you saying that the 16-bit mode on the likes of an MMx or ARMmite does not work in 16-bit mode on my adaptor?

I have a MMx here somewhere - now I will have to hook it up. I never tried it on the MMx, as if it was working in 8-bit on the E100, I figured we'd be fine in 16-bit.

False logic perhaps.

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KeepIS
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Posted: 06 November 2018 at 5:46pm | IP Logged Quote KeepIS

No your adapter is fine and I had it working in 16 Bit mode with the ARMmite, but it was flaky because of the connecting cable from the A-H7 board to the LCD connector, which plugs into the Adaptor.

FYI: I checked every connection on your adaptor Board and they are 100% correct, this all has to do with the 9" LCD being really sensitive to lead capacitance and resistance as described in the first post.

So your Adaptor board and the A-H7 Backpack should work 100% , I'll confirm that when I get the Backpack board built.


Edited by KeepIS on 06 November 2018 at 5:47pm


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Posted: 06 November 2018 at 5:49pm | IP Logged Quote Grogster

Cool, nice to know, thanks.

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KeepIS
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Posted: 07 November 2018 at 9:02pm | IP Logged Quote KeepIS

Soldered the sockets and pins to the ARMmite Backpack, nothing else as the components have not arrived yet. Removed the links as per Peters Manual for the ARMmite H7, flashed the latest MM.Basic ARMmite firmware and set the options for the 9" LCD in 16 bit mode with Touch, loaded my Program and plugged in Grosters 7" to 9" E100 Adaptor and then the EastRising 9" LCD.

Powered it with my LAB power supply with 5v to the EV5 pins and instantly greeted with the MM.BASIC copyright message and a command prompt - perfect.

Plugged in my wireless USB keyboard and did a GUI calibrate - perfect, typed RUN and the my program displayed with every graphical element perfect and not a trace of noise or instability.

So basically the backpack at the moment is running as a PCB connection between the ARMmite LCD IO pins and via the small 7" to 9" PCB Adaptor into the display.

Well Done Groster for the 7" to 9" adaptor PCB, and matherp for the backpack board and design. Brilliant - that backpack board pretty much makes the ARMmite-H7 as easy as the Micromite Plus to use.

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